Python Code In Work Area
Well... Now I am really showing my ignorance about Blender. Last night I tried everything I could think of. I clicked on anything and everything that looked like it might be the right thing to change it back, and found nothing. But as I was making a screenshot, I saw a button I didn't see last night (my vision is clearer this morning) and I don't remember what the label said exactly, but "previous" was part of it, so I clicked on it and it changed it back to the model I had been trying to export last night.

But it's Murphy's Law of Seeking Help... As soon as you ask for help, you figure it out yourself! 

Thanks anyway...